1. Field of the Invention
The present invention relates to a semiconductor device and a method for manufacturing the semiconductor device. The present invention particularly relates to a semiconductor device including a photoelectric conversion device.
2. Description of the Related Art
Sensors which detect visible light having a wavelength range of from 400 nm to 700 nm are referred to as optical sensors or visible light sensors. Applications of the optical sensor or the visible light sensor such as detecting a light signal in order to read information, and detecting brightness of the ambient environment in order to control operation of electronic devices or the like are known.
For example, an optical sensor is used in a mobile phone or a television device so that brightness of a display screen is adjusted according to brightness of the ambient environment of the mobile phone or the television device.
Such a semiconductor device, for example, the optical sensor or the visible light sensor, is formed in such a manner that transistors are formed over a substrate such as glass, a wafer, or the like, and the substrate is cut (divided).
In many cases, a substrate is divided as follows. First, a groove (also referred to as a scribe line) is formed on the surface of the substrate by using a scribing apparatus. Then, the substrate is forced to be divided along the groove by using a cutting apparatus. Alternatively, in the division of the substrate using a laser beam, the substrate is selectively irradiated with a laser beam for being locally heated. Then, the surface of the substrate which is heated is cooled by a refrigerant. Subsequently, a crack is formed by utilizing thermal stress which is generated in the substrate, and thus the substrate is divided (for example, see Patent Document 1: Japanese Published Patent Application No. 2001-64029).